1. Field of the Invention
The present invention relates generally to the methods and means for displaying curve patterns on the screen of a video display unit, such as the screen of a conventional home television receiver.
2. Background of the Invention
In the journal Elektor, December 1971, pages 1234-1242, an apparatus is disclosed for the generation of the potential pattern of a periodic signal on the cathode ray tube of a home television receiver operating according to the image raster process. In the disclosed device, a comparator is used to compare a horizontal frequency saw-tooth signal with a signal which is to be displayed. When an equal potential is reached, the electron beam of the cathode ray tube is scanned bright. However, in this operating mode, the potential pattern of the signal which is to be generated is rotated by 90.degree., that is, it is represented vertically. Furthermore, only signals having a frequency of less than the horizontal deflection frequency of the cathode ray tube of the home receiver can be reproduced in this manner.
Another circuit arrangement has been disclosed in German Patent Application No. P2638858 now U.S. Pat. No. 4,145,706 by which horizontal periods of a video signal can also be represented in the horizontal position of the cathode ray tube of a video display device. In this disclosure, a vertical frequency saw-tooth signal is fed into the comparator.
It is an object of the present invention to construct an improved device over the prior art which is capable of reproducing any curve pattern, for example vector illustrations, on the screen of a video display unit such as a conventional home television receiver.